The American Academy of Dermatology describes dandruff as a common scalp condition in which small pieces of dry skin flake off the scalp. Its advice is practical: look for a dandruff shampoo with an active like zinc pyrithione, salicylic acid, sulfur, selenium sulfide or ketoconazole, and protect your scalp from the sun, because a sunburn on the scalp can increase flaking.

That last point stuck with me. We think of the scalp as hair territory, but it is skin, and it gets dry, tight, oily, sensitive and sunburned like the rest of you. Scalp serums are the leave-on side of that care. They do not replace a medicated shampoo, but they can keep a dry or irritated scalp comfortable between washes.

Most of the scalp serums here borrow straight from face skincare: hyaluronic acid, niacinamide, barrier support, prebiotics and salicylic acid. A few lean on older ideas, like amla from Ayurveda, tea tree and peppermint. They are skincare rather than medicine, which is why they sit alongside a dandruff shampoo instead of replacing it.

The first grid is daily serums for dry, itchy scalps. The second covers exfoliants, oils and overnight serums for when a daily serum is not enough. My tip: part your hair into four sections and apply along each part, directly on the skin. Serum on your lengths does nothing for your scalp.

The Ordinary Natural Moisturizing Factors + HA Scalp Serum is a milky, fragrance-free serum built from the same kind of moisturizing factors your skin makes, plus squalane. It is the simplest place to start, and the one I would pick for a scalp that just feels tight after washing. Act+Acre makes two here. Daily Hydro is the everyday hydrator, with multi-molecular hyaluronic acid and amino acids. Microbiome Cooling is the one for itch, with peppermint oil, and the brand says it relieves a dry, itchy scalp in 30 seconds and reduces loose flakes.

Kérastase Nutritive Hydrating Scalp Serum uses plant proteins and niacinamide and has a fresh scent. Olaplex N°.0.5 brings the brand's bond-building technology to the scalp barrier and targets visible scalp aging. Crown Affair The Calming Scalp Serum blends hyaluronic acid with aloe and tea tree oil for redness and flaking, and it is vegan.

Briogeo Scalp Revival uses binchotan charcoal, peppermint and tea tree oils with witch hazel, so it is the pick if your scalp is itchy and oily at once. OUAI Hydrating Scalp Serum is the most reviewed in this edit, with adaptogens, hyaluronic acid and peptides, and it is made to soothe irritation from styling.

What I would skip: a cooling peppermint serum on a scalp that is already raw or cracked. Peppermint feels good on itch and less good on broken skin, so choose a fragrance-free option instead.

If a daily serum is not enough, this grid is where I would look next.

For buildup, Virtue Exfoliating Scalp Treatment is a whipped cream with rice beads, papain and bromelain enzymes, and BHA. Moroccanoil Dry Scalp Treatment is a five-minute pre-shampoo serum with salicylic acid and argan oil for dry, flaky scalps.

For nights, Virtue Overnight Scalp & Hair Serum works while you sleep, with Alpha Keratin 60ku and hyaluronic acid, and the brand describes it as nongreasy. Kérastase Potentialiste uses prebiotic fractions and vitamin C to protect the scalp barrier from daily stressors.

For oils, Fable & Mane SahaScalp is a weightless oil serum built around amla, an Indian gooseberry rich in vitamin C, and it suits sensitive scalps. Dr. Groot Scalp Barrier Boost is an oil-in-serum with biotin and rosemary oil that reduces buildup and supports the barrier.

Living Proof Scalp Care Dry Scalp Treatment is a leave-in with a hyaluronic acid patch and a vitamin B3 complex, made for lasting relief from flaking and itch. Sisley Revitalizing Fortifying Serum is concentrated in plant extracts like sage, plus rice proteins, and gives limp roots a lift without weighing hair down.

A pairing tip: exfoliate once a week, then use a hydrating serum on the other days.

What I would skip: an exfoliating treatment and a salicylic acid shampoo in the same week. Your scalp does not need to be scrubbed twice.

I think scalp serums make the most sense once you stop thinking of your scalp as hair and start thinking of it as skin. Hydrate it when it is dry, calm it when it itches, and exfoliate it when products build up. Give a serum a few weeks, and apply it to the skin, not the hair. If thick flakes keep coming back, see a board-certified dermatologist, because that can be seborrheic dermatitis or psoriasis rather than simple dryness.